Valve arrangement for regeneratively heated furnace



Get. 27, 1959 I F. WITTLER' 2,910,284.

VALVE ARRANGEMENT FOR REGENERATIVELY HEATED FURNACE Filed March 19, 19562 Sheets-Sheet 1 FIG. I

INVEN TOR.

BY 5 .LLMmQ Qua-L ATTORNEYS Oct. 27, 1959 F. WlTTLER VALVE ARRANGEMENTFOR REGENERAT IVELY HEATED FURNACE Fild March 19, 1956 FIG. 2

13 1 M 14 12 f I 1] 12a 6 2 Sheets-Sheet 2 FIG. 3

7 14 a l "i 12 Hi] I 12a T1! 6 \INVENTOR.

ATTORNEYS. v

VALVE ARRANGEMENT FOR REGENERATIVELY HEATED FURNACE Fritz Wittler,Duran, Rhineland, Germany, assignor to Zimmermann and Jansen G.m.b.H.,Duran, Rhineland, Germany, a corporation of Germany Application March19, 1956, Serial No. 572,443

6 Claims. (Cl. 263-45) The invention relates to valve arrangements forair and flue gases in regeneratively heated industrial furnaces, inparticular SM furnaces. Various systems for this purpose are known. Theslide valve system has two slide valves for gas and two dampers for air,the latter of throttling type. In setting up such a system, the verticalducts in which the air dampers are installed must always be placedperpendicular to the passages. The resulting unavoidable changes ofdirection in the combustion air line and in the passage involvesubstantial pressure losses. To this is added the fact that in the partof the combustion air line shut 01f after actuation, a pressure cushionmust be formed before flow of combustion air to the combustion chamberbecomes possible. In case of any electric power failure, such a systemmust be actuated by emergency manual mechanisms. These, unlike theelectrical controls, do not ensure that the switchover process will takeplace in proper sequence. Such a system has the additional disadvantageof being very expensive because of its heavy gas slide valve. Exhaustgas flow, on the other hand, is advantageous. Use of air interchangeflaps such as the Siemens or Simplex type is desirable for reasons ofprice. Aerodynamically, these have major disadvantages in comparison toslide controls because both exhaust gases and combustion air are subjectto considerable pressure and draft losses due to sharp turns. Besides,fresh air always enters the exhaust or stack passage during theswitchover operation. The disadvantages enumerated also apply to knowntwin-deck slide valves.

The invention addresses itself to the problem of eliminating thesedisadvantages and difficulties by simple means. it may be said toconsist essentially in that the air and gas branchings, located separatefrom each other, are close together, and their corresponding valve meanshave a common mechanism.

The object of this invention is to provide in a regeneratively heatedfurnace having two air passages and two exhaust passages valve meanswhich effectuate a switchover from one path for air and exhaust gases tothe other path in proper sequence and where the switchover iseffectuated by a single control for the valve means.

A further object is to provide in a regeneratively heated furnace havingtwo air passages and two exhaust passages valve means which preventfresh air from entering either stack passage when the switchover fromone exhaust passage to the other is effectuated.

The object of the invention is illustrated in the drawings, in which:

Fig. 1 is a plan view of the furnace and the valve arrangernent thereforaccording to the invention, with parts broken away, and

Figs. 2-5 are views of the valve arrangement, on a larger scale and withparts broken away, illustrating the various positions thereof.

The two passages 2 and 3 in Fig. 1 open at reference numeral 4 into theflue or stack passage 1. At branching 4, there is a flap 5 serving tocontrol the flue gas. Outsidethe passage, acompression spring drotatable about a fixed point Q is provided, whose free end e ispositively connected to the mechanism of the gas flap in such mannerthat in each extreme position, a pressure tends to hold the flap tightlyagainst the seat. The combustion air supply line is designated 6; it hastwo branches 7 and 8, merging obliquely into passages 2 and 3 at 9 and10. Beyond 9 and lit, where passages 7 and 8 merge into passages 3 and2, passages 3 and 2 extend into the furnace 2-2 at its respectiveopposite heads 26 and 21. At the branching 11 of the air duct, in theform of a Y, there are two flaps 12 and 12a. These two control flaps 12and 12a tend to push away from each other under the action of a springprovided at pivot p.

This arrangement of thet air duct makes it possible to place branchings4 and 11 close together so that their control means 5, 12, 12a may beactuated by a common mechanism, that will positively switch the controlmeans even when operated by emergency manual action; that is, no freshair will enter the departing flue gas during the control operation,thereby avoiding explosion hazard, even though the contents of the gaschamber pass off to the stack after switchover.

In the embodiment shown in the drawings, the exhaust line leading to thestack bears reference numeral 1. Lines 2 and 3 coming from the furnaceopen into it. These two lines 2 and 3, at branching 4, are connected toor disconnected from the exhaust line 1 by means of flap 5. Aboveexhaust line 1 there is an air supply line 6 branching at 11 into lines7 and 8. Branches 7 and 3 open into lines 2 and 3 leading to thefurnace.

In the embodiment shown, the shut-off means at the air branching 11consists of two control flaps l2 and 12a. These two air control flapstend to push away from each other under the action of a spring S placedat pivot p.

The control system as a whole is actuated from the shaft at pivot p.This brings about partial revolutions of a disc 13 or the like. Disc 13has a gear sector 14 en.- gaging a gear sector 15 of a disc 16. Disc 16is mounted on a shaft 17 for control flap 5 in the gas branching .4.

In the position of the control system as represented in Fig. 2, thecontrol fiaps 12 and 12a of air line 6, 7, 8 and 11 are close togetherso as to shut off all communication between air supply line 6 and branch7 while allowing free passage of air from supply linen to branch 8.Control flap 5 at branching 4 shuts off all communication betweenexhaust line 1 and exhaust line 2 while allowing free passage of exhaustgases frorrrline 3 to line 1 which leads to the stack. The operatingcycle for Fig. 2 isthus as follows: air flows through line 6 into line8; from line 8 it merges into line 2 which extends into the furnace 22at head 21. The exhaust gases leave the opposite head 20 of the furnacethrough exhaust line 3 into exhaust line 1, leading to the stack.

For switching the air and exhaust lines, shaft p is first turned. Thisleaves flap 1'2 stationary, while flap 12a shuts off line 8. As aresult, air line 6 is shut off. During rotation of shaft 2, sector 14 ofdisc 13 meets sector 15 of disc 16. Prior to this rotation of disc 13,disc 16 has not changed position. This phase of the process isillustrated in Fig. 3.

If shaft p is rotated farther, control flaps 12 and 12a remain in closedposition. Gears 14 and 15 engage, so that flap 5 at branching 4 movesinto the opposite control position. In this position, the exhaust passesfrom the outer furnace head 21 through line 2 into stack line '1. Theair line 6 is still closed. This phase of the process is shown in Fig.4.

This is followed by further rotation of shaft p as shown in Fig. 5.During such continued motion, control flap 12 swings against flap 12a.This allows free passage of air from supply line 6 to line 7. Theoperating cycle for Fig, 5 is thus as follows: air flows through line 6into line 7 5 from line 7 it merges into line 3 which extends into thefurnace at 20. The exhaust gases leave the furnace at 21 through exhaustline 2, into exhaust line 1, leading to the stack.

The control flap at branching 4 is held in its extreme positions by anaccumulator such as spring :1. One end e of this accumulator, in theembodiment shown in the drawing, is articulated to disc 16, while theother end Q has a fixed pivot. During the partial revolution of disc 16from one extreme position to the other, the accumulator d is wound upuntil the distance between joints e and Q has attained a minimum. Uponfurther rotation, the accumulator d unwinds so that flap 5, uponreaching its extreme position, is pressed tightly on the seat.

The design and arrangement of components according to the inventionembodies the advantage that during switchover, air supplied to onefurnace head cannot come in contact with the exhaust flowing to thepassage. This is accomplished in that the air line is first closed, andthe exhaust line switched over with the air line in that condition. Onlythen is the air line opened.

While I have shown and described the preferred embodiments of myinvention, it will be understood that various changes may be made in theidea or principles of the invention within the scope of the appendedclaims.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a regeneratively heated furnace, a main air conduit having branchconduits in fluid communication therewith at a first junction, a mainflue conduit having branch conduits in fluid communication therewith ata second junction, said main and branch air conduits being insubstantial juxtaposed relation with the corresponding flue conduits,respectively, said air branch conduits having end portions convcrginglydisposed relative to said flue branch conduits, each air branchcommunicating with its corresponding flue branch conduit, at a third andfourth junction, respectively, a common conduit extending from each ofsaid third and fourth junctions into opposite ends, respectively, ofsaid furnace, first valve means for said air branch conduits disposed atthe first junction, second valve means for said flue branch conduitsdisposed at the second junction, and common operating mechanism for saidfirst and second valve means whereby to place the latter in differentcoordinated fluid controlling positions with respect to their companionbranch conduits, said first valve means comprising a valve member foreach of said air branch conduits for controlling the air flow throughthe latter, and said second valve means comprising a single flue valvemember pivotally movable from a first position in which one of said fluebranch conduits is in direct fluid communication with said main flueconduit and the other of said flue branch conduits is closed to a secondposition in which the other of said flue branch conduits is in directfluid communication with said main flue conduit and the one of saidbranch conduits is closed.

2. In a regeneratively heated furnace, a main air conduit having branchconduits in fluid communication therewith at a first junction, a mainflue conduit having branch conduits in fluid communication therewith ata second junction, said main and branch air conduits being insubstantial juxtaposed relation with the corresponding flue conduits,respectively, said air branch conduits having end portions convcrginglydisposed relative to said flue branch conduits, each air branchcommunicating with its corresponding flue branch conduit, at a third andfourth junction, respectively, a common conduit extending from each ofsaid third and fourth junctions into opposite ends, respectively, ofsaid furnace, first valve means for said air branch conduits disposed atthe first junction, second valve means for said flue branch conduitsdisposed at the second junction, and common operating mechanism for saidfirst and second valve means whereby to place the latter in difierentcoordinated fluid controlling positions with respect to their companionbranch conduits, said first valve means comprising a valve member foreach of said air branch conduits for controlling the air flow throughthe latter, and said second valve means comprising a single flue valvemember pivotally movable from a first position in which one of said fluebranch conduits is in direct fluid communication with said main flueconduit and the other of said fine branch conduits is closed to a secondposition in which the other of said flue branch conduits is in directfluid communication with said main flue conduit and the one of saidbranch conduits is closed, a shaft pivotally mounting said air valvemembers, and resilient means mounted on said shaft and biasing said airvalve members away from each other.

3. In a regeneratively heated furnace, a main air conduit having branchconduits in fluid communication therewith at a first junction, a mainflue conduit having branch conduits in fluid communication therewith ata second junction, said main and branch air conduits being insubstantial juxtaposed relation with the corresponding flue conduits,respectively, said air branch conduits having end portions convcrginglydisposed relative to said flue branch conduits, each air branchcommunicating with its corresponding flue branch conduit, at a third andfourth junction, respectively, a common conduit extending from each ofsaid third and fourth junctions into opposite ends, respectively, ofsaid furnace, first valve means for said air branch conduits disposed atthe first junction, second valve means for said flue branch conduitsdisposed at the second junction, and common operating mechanism for saidfirst and second valve means whereby to place the latter in differentcoordinated fluid controlling positions with respect to their companionbranch conduits, said first valve means comprising a valve member foreach of said air branch conduits for controlling the air flow throughthe latter, and said second valve means comprising a single flue valvemember pivotally movable from a first position in which one of said fluebranch conduits is in direct fluid communication with said main flueconduit and the other of said flue branch conduits is closed to a secondposition in which the other of said flue branch conduits is in directfluid communication with said main flue conduit and the one of saidbranch conduits is closed said common operating mechanism includingmeans providing for the closing of said air branch conduits prior to themovement of said second valve means from one of said positions to theother of said positions whereby to prevent the mixture of air and gasduring said movement of said second valve means.

4. In a regeneratively heated furnace, a main air conduit having branchconduits in fluid communication therewith at a first junction, a mainflue conduit having branch conduits in fluid communication therewith ata second junction, said main and branch air conduits being insubstantial juxtaposed relation with the corresponding flue conduits,respectively, said air branch conduits having end portions convcrginglydisposed relative to said flue branch conduits, each air branchcommunicating with its corresponding flue branch conduit, at a third andfourth junction, respectively, a common conduit extending from each ofsaid third and fourth junctions into opposite ends, respectively, ofsaid furnace, first valve means for-said air branch conduits disposed atthe first junction, second valve means for said flue branch conduitsdisposed at the second junction, and common operating mechanism for saidfirst and second valve means whereby to place the latter in differentcoordinated fluid controlling positions with respect to their companionbranch conduits, said first valve means comprising a valve member foreach of said air branch conduits for controlling the air flow throughthe latter, and said second valve means comprising a single flue valvemember pivotally movable from a first position in which one of said fluebranch conduits is in direct fluid communication with said main flueconduit and the other of said flue branch conduits is closed to a secondposition in which the other of said flue branch conduits is in directfluid communication with said main flue conduit and the one of saidbranch conduits is closed,

a shaft pivotally mounting said air valve members, and

resilient means mounted on said shaft and biasing said air valve membersaway from each other, a shaft mounting said single flue valve member forpivotal movement between the two positions thereof, and means forbiasing said flue valve member in said different positions thereof.

5. In a regeneratively heated furnace, a main air conduit having branchconduits in fluid communication there with at a first junction, a mainflue conduit having branch conduits in fluid communication therewith ata second junction, said main and-branch air conduits being insubstantial juxtaposed relation with the corresponding flue conduits,respectively, said air branch conduits having end portions converginglydisposed relative to said flue branch conduits, each air branchcommunicating with its corresponding flue branch conduit, at a third andfourth junction, respectively, a common conduit extending from each ofsaid third and fourth junctions into opposite ends, respectively, ofsaid furnace, first valve means for said air branch conduits disposed atthe first junction, second valve means for said flue branch conduitsdisposed at the second junction, and common operating mechanism for saidfirst and second valve means whereby to place the latter in differentcoordinated fluid controlling positions with respect to their companionbranch conduits, said first valve means comprising a valve member foreach of said air branch conduits for controlling the air flow throughthe latter, and said second valve means comprising a single flue valvemember pivotally movable from a first position in which one of said fluebranch conduits is in direct fluid communication with said main flueconduit and the other of said flue branch conduits is closed to a secondposition in which the other of said flue branch conduits is in directfluid communication with said main flue conduit and the one of saidbranch conduits is closed, a shaft pivotally mounting said air valvemembers, and resilient means mounted on said shaft and biasing said airvalve members away from each other, a shaft mounting said single fluevalve member for pivotal movement between the two positions thereof, andmeans for biasing said flue valve member in said different positionsthereof, and means operatively connecting said shafts for moving saidsingle flue valve member to a different position'subsequent to thepositioning of said air valve members in air branch conduit closingpositions.

6. In a regeneratively heated furnace, a main air conduit having branchconduits in fluid communication therewith at a first junction, a mainflue conduit having branch conduits in fluid communication therewith ata second junction, said main and branch air conduits being insubstantial juxtaposed relation with the corresponding flue conduits,respectively, said air branch conduits having end portions converginglydisposed relative to said flue branch conduits, each air branchcommunicating with its corresponding flue branch conduit, at a third andfourth junction, respectively, a common conduit extending from each ofsaid third and fourth junctions into opposite ends, respectively, ofsaid furnace, first valve means for said air branch conduits disposed atthe first junction, second valvemeans for said flue branch conduitsdisposed at the second junction, and common operating mechanism for saidfirst and second valve means whereby to place the latter in differentcoordinated fluid controlling positions with respect to their companionbranch conduits, said first valve means comprising a valve member foreach of said air branch conduits for controlling the air flow throughthe latter, and said second valve means comprising a single flue valvemember pivotally movable from a first position in which one of said fluebranch conduits is in direct fluid communication with said main flueconduit and the other of said flue branch conduits is closed to a secondposition in which the other of said flue branch conduits is in directfluid communication with said main flue conduit and the one of saidbranch conduits is closed, a shaft pivotally mounting said air valvemembers, and resilient means mounted on said shaft and biasing said airvalve members away from each other, a shaft mounting said single fluevalve member for pivotal movement between the two positions thereof, andmeans for biasing said flue valve member in said different positionsthereof, and means operatively connecting said shafts for moving saidsingle flue valve member to a diflerent position subsequent to thepositioning of said air valve members in air branch conduit closingpositions, said connecting means comprising companion segmental gearssecured to said shafts, respectively, and operatively engageable formoving said flue valve member under the control of said operating shaft.

References Cited in the file of this patent UNITED STATES PATENTS1,814,567 Merkt July 14, 1931 1,825,815 Nye Oct. 6, 1931 2,098,553Reiner NOV. 9, 1937 FOREIGN PATENTS 114,589 Great Britain Apr. 11, 1918

